1. Field of the Invention
This invention generally relates to diamond bonded constructions and, more particularly, to diamond bonded constructions that are specially engineered with a diamond body that is attached to a substrate other than the one used for sintering the diamond body at high pressure/high temperature conditions to provide improved performance properties and service life when compared to conventional diamond bonded constructions.
2. Background of the Invention
The use of constructions comprising a body formed from ultra-hard materials such as diamond, polycrystalline diamond (PCD), cubic boron nitride (cBN), polycrystalline cubic boron nitride (PcBN) are well known in the art. An example of such constructions may be found in the form of cutting elements comprising an ultra-hard component or body that is joined to a metallic component or substrate. In such cutting elements, the wear or cutting portion is formed from the ultra-hard component and the metallic portion is provided for the purpose of attaching the cutting element to a desired wear and/or cutting device. In such known constructions, the ultra-hard component may be formed from those ultra-hard materials described above that provide a high level of wear and/or abrasion resistance that is greater than that of the metallic component.
The use of PCD as an ultra-hard material for forming such constructions is well known in the art. PCD is formed by subjecting a volume of diamond grains to high pressure/high temperature (HPHT) conditions in the presence of a suitable catalyst material, such as a solvent catalyst metal selected from Group VIII of the Periodic table. Oftentimes, the source of the solvent catalyst material used to form PCD is the substrate, wherein the solvent catalyst material is present as a constituent of the substrate that migrates therefrom and infiltrates into the adjacent diamond body during HPHT processing. The resulting construction is a PCD compact comprising the PCD body joined to the substrate.
An issue known to exist with such conventional PCD compact constructions is the existence of residual stress within diamond body adjacent the region interfacing with the substrate that is created during HPHT processing. Such residual stress may cause cracking within the diamond body when the compact is placed in a wear or cutting operation that may result in premature compact failure. Additionally, while the substrates used to make such conventional PCD compact constructions may have properties desired to facilitate sintering of the diamond body during HPHT processing, e.g., properties associated with solvent catalyst metal content and/or type, such substrates may not have the most desired properties for the ultimate use of the compact in a wear or cutting operation, e.g., may not have a desired degree of erosion resistance, thereby possibly limiting the effective service life of the compact.
It is, therefore, desirable that diamond bonded constructions be constructed in a manner that provides a reduced or eliminated degree of residual stress when compared to conventional PCD compact constructions. It is also desired that such diamond body constructions be constructed in a manner comprising a substrate having improved end-use service properties when compared to conventional PCD compact constructions. It is further desired that such diamond bonded constructions provide these improved properties without sacrificing desired properties of wear resistance, abrasion resistance, impact resistance, and fracture toughness when compared to conventional PCD compact constructions. It is still further desired that such diamond bonded constructions be produced in a manner that is efficient and does not involve the use of exotic materials and/or techniques.